When total_req_power is 0, divvy_up_power() will set granted_power to 0,
and cdev will be limited to the lowest performance. If our polling delay
is set to 200ms, it means that cdev cannot perform better within 200ms
even if cdev has a sudden load. This will affect the performance of cdev
and is not as expected.

For this reason, if nobody requests power, then set the granted power to
the max_power.

Signed-off-by: zhengshaobo1 <zhengshaobo1@xiaomi.com>

Bug: 375959779
Bug: 399554103
(cherry picked from commit 08eb0493
 https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git

 thermal)
Change-Id: I6e7360d8e6b886d9f1f23e9e4fd41f197605d520
Signed-off-by: zhengshaobo1 <zhengshaobo1@xiaomi.com>
(cherry picked from commit 0061c689)